The link says "Professional Installation recommended". (To which many on this forum I'm sure would say "garbage").
Is there a thread on the forum for mounting the backup camera?
Bob - there are many backup camera installation threads on this forum dating from years ago through present. I can say that even with wireless cameras mounted on the rear of the RV, DC power is still required and that's not wireless. Some have chosen to tap into the marker light circuit in the rear cap. By doing so, no separate DC power line needs to be run and the camera gets turned off each time the running lights circuit is turned off.
For those who choose to run their own DC power wire, the typically fish a line from near the center marker light at the top of the rear cap, over to the corner marker light, then down to the tail light, then into the underbelly and up to the front of the coach. They typically use the same path for the A/V output if not a wireless camera.